δ-Bonding modulates the electronic structure of formally divalent nd¹ rare earth arene complexes

Chemical Science, Journal Year: 2024, Volume and Issue: 15(37), P. 15160 - 15169

Published: Jan. 1, 2024

Landmark advances in rare earth (RE) chemistry have shown that divalent complexes can be isolated with non-Aufbau 4f n {5d/6s}1 electron configurations, facilitating remarkable bonding motifs and magnetic properties. We report a series of bis-tethered arene complexes, [RE(NHAriPr6 )2] (2RE; RE = Sc, Y, La, Sm, Eu, Tm, Yb; NHAriPr6 {N(H)C6H3-2,6-(C6H2-2,4,6-iPr3)2}). Fluid solution EPR spectroscopy gives g iso < 2.002 for 2Sc, 2Y, 2La, consistent formal nd1 calculations reveal metal-arene δ-bonding via mixing nd(x 2-y 2) valence electrons into π* orbitals. Experimental calculated UV-Vis-NIR spectroscopic properties 2Y show minor structural changes markedly alter the metal d(x contribution to SOMO. This contrasts where d-based resides non-bonding orbital. Complexes 2Sm, 2Eu, 2Tm, 2Yb contain highly-localised n+1 ions no appreciable by density functional calculations. These results physicochemical both configurations are nuanced, may controlled through ligand modification, require multi-pronged experimental theoretical approach fully rationalise.

Language: Английский

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The Scandium(II) Carbonyl Complex (C₅H₂^tBu₃)₂Sc(CO) and Its Isocyanide Analog (C₅H₂^tBu₃)₂Sc(CNC₆H₃Me₂-2,6)

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(36), P. 24770 - 24775

Published: Aug. 27, 2024

Treatment of the scandium(II) metallocene Cp

Language: Английский

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Room-Temperature H₂ Splitting and N₂-Hydrogenation Induced by a Neutral Lu^II Complex

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 5, 2025

The direct splitting of H2 and N2 molecules is a challenging reaction that closely related to the Haber-Bosch ammonia synthesis process. Until now, such reactivity has never been observed in case molecular lanthanide species. Here, we show careful selection ligand scaffold allows isolation characterization kinetically stable but highly reactive LuII complex. This divalent species enables at room temperature, an unknown chemistry, which fully corroborated by DFT calculations. In addition, complex readily binds N2, leading end-on coordinated diazenido (N2)2- latter can be hydrogenated under very smooth conditions (ca. 1.2 bar H2, ambient temperature) form unique LuIII-NH2 Direct hydrogenation cleavage are thus accessible using low-valent rare-earth metal complexes.

Language: Английский

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Redox Studies of the Scandium Metallocene (C₅H₂^tBu₃)₂Sc^II Lead to a Terminal Side-On (N═N)^2– Complex: [(C₅H₂^tBu₃)₂Sc^III(η²-N₂)]⁻

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

Cyclic voltammetry measurements on the scandium(II) metallocene, Cpttt2ScII (Cpttt = C5H2tBu3), reveal a -1.87 V vs Fc+/Fc event assigned to [Cpttt2Sc]+/0 redox couple and -3.09 process [Cpttt2Sc]0/- couple, which are consistent with subsequent chemical studies. Chemical oxidation of AgBPh4 gives scandocenium cation salt [Cpttt2ScIII][BPh4], 1. The [Cpttt2ScIII]+ does not coordinate [BPh4]- anion or THF solvent; however, one methyl groups tert-butyl substituent has close interaction Sc(III) ion. Decomposition occurs in presence [nBu4N][PF6] supporting electrolyte, studies indicate that 1 reacts [PF6]- by fluoride abstraction form Cpttt2ScIIIF PF5. reduction proceeds Cp*2SmII Cp*2CoII (Cp* C5Me5), is measured potentials. was observed react N2; treatment KC8 18-crown-6 (crown) under N2 forms (N═N)2- complex, Cpttt2ScIII(μ-η2:η2-N2)K(crown), 2. reaction 2.2.2-cryptand (crypt) generates [K(crypt)][Cpttt2ScIII(η2-N2)], 3, first isolable complex any metal terminal side-on ligand. These LnIIA2/M/N2 reactions (M alkali metal; (A)- anion) Ln(II)/Ln(I) analogs previously reported Ln(III)/Ln(II) reactions, LnIIIA3/M/N2, Ln(III) complexes Ln(II) reactivity complexes.

Language: Английский

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Theoretical Characterization of Bis(pentaisopropylcyclopentadienyl) Rare-Earth Metallocenes

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: May 6, 2025

We report ground states, equilibrium structures, and both electronic electron paramagnetic resonance (EPR) spectra of divalent rare-earth metallocenes Ln(CpiPr5)2 as obtained from scalar exact two-component (X2C) relativistic density functional theory (DFT) calculations. While the results for with Ln = Nd, Sm, Eu, Tm, Yb are consistent a conventional (4f)n+1 configuration metal atom, La, Ce, Gd, Lu best described having (4f)n(5d)1 states. Strong mixing is observed Pr; Ho Er, two distinct states character energetically close, comparison available experimental data slightly favors ground-state assignment. Our show that Nd Pr compounds have strong or partial character, suggesting previous assignments based solely on atomic f-d splittings [McClain, K. R. J. Am. Chem. Soc. 2022, 144, 22193-22201. 10.1021/jacs.2c09880] should be revised. X2C calculations EPR parameters magnitude isotropic hyperfine coupling (HFC) relative to an reference poor descriptor s/d mixing, this approach unreliable compounds. A massive HFC constant 4401 MHz predicted compound.

Language: Английский

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Dinitrogen reduction chemistry with scandium provides a complex with two side-on (NN)²⁻ ligands bound to one metal: (C₅Me₅)Sc[(µ-η²:η²-N₂)Sc(C₅Me₅)₂]₂

Chemical Science, Journal Year: 2024, Volume and Issue: 15(39), P. 16069 - 16078

Published: Jan. 1, 2024

A new structural type in dinitrogen chemistry has been obtained by the attempted one electron reduction of a bridging (NN) 2− complex scandium.

Language: Английский

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Large- and Small-Scale Syntheses of Donor-Free Rare-Earth Triiodides from the Metals and Ammonium Iodide

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(36), P. 16855 - 16860

Published: Aug. 26, 2024

Rare-earth triiodides free of donor solvents, LnI3 (Ln = Sc, Y, La–Lu), have been prepared in quantities as high 76 g and yields between 72% (Sc) 98% (La) by the reaction corresponding metal excess ammonium iodide a two-step, one-pot procedure that is conducted borosilicate glassware at temperatures 350–430 °C commercial tube furnaces. Procedures for both large-scale small-scale syntheses are described, with specific examples Ln La, Pr, Nd, Gd, Dy, Ho, Lu. While synthesis described here utilizes specialized glassware, preparation may be performed commercially available glassware.

Language: Английский

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δ-Bonding versus Electron Localization in Formally Divalent Rare Earth Complexes

Published: March 13, 2024

Herein we present a series of room-temperature stable, structurally analogous rare-earth complexes the form [M(NHAriPr6)2] (M = Sc, Y, La, Sm, Eu, Tm, Yb; NHAriPr6 {N(H)C6H3-2,6-(C6H2-2,4,6-iPr3)2}). All seven contain formal M(II) ions with close M···arene contacts. The Sc(II) and La(II) display an open-book deformation (ca. 11–13°) one metal-bound arene, while for Y(II) there are two symmetry-equivalent Y···arene interactions smaller deformations 7°). In case Sc(II), Y(II), La(II), quantum chemical calculations reveal delocalization metal d-electron from into ligand π-orbitals forming δ-bonding interactions. EPR UV-Vis-NIR spectroscopies combined show structural change in solution to single-open-book structure common La(II). While Sm(II), Eu(II), Tm(II), Yb(II) retain similar contacts, their 4fn+1 valence electron configurations do not lead interactions; however, NMR studies diamagnetic 4f14 171Yb···1H coupling arene ring-protons at room temperature that interaction is preserved across wide range. These represent rare which extends group 3 elements lanthanide includes extremely neutral complex.

Language: Английский

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Synthesis and Structure of Silyl-Substituted Bis(cyclopentadienyl) Scandium(III) Halide Complexes

Organometallics, Journal Year: 2024, Volume and Issue: 44(1), P. 137 - 147

Published: Dec. 18, 2024

Despite the importance of bis(cyclopentadienyl) scandium(III) halide complexes as precursors in development scandium metallocene chemistry, relatively few examples this class have been structurally characterized. Since cyclopentadienyl ring substitution pattern and identity can a major influence on organoscandium complex synthesis reactivity, it is critical to variety well-characterized [(C5R5)2ScX]n starting materials (R = H, alkyl, silyl; X halide) available for exploration area. To remedy deficiency, reactions between ScX3 (X Cl I) 2 equiv potassium cyclopentadienide reagents examined. This has provided, good crystalline yield, compounds [C5H3(SiMe3)2]2ScI, [C5Me4(SiMe3)]2ScI, [C5Me4(SiMe2tBu)]2ScI, {[C5H4(SiMe3)]2Sc(μ-I)}2, {[C5H4(SiiPr3)]2Sc(μ-I)}2, {[C5H3(SiMe3)2]2Sc(μ-Cl)}2, each which characterized by X-ray crystallography, elemental analysis, NMR spectroscopy (1H, 13C{1H}, 29Si{1H}, 45Sc), infrared spectroscopy. The study also revealed facile cocrystallization oxide {[C5H3(SiMe3)2]2Sc}2(μ-O) hydroxide {[C5H3(SiMe3)2]2Sc(μ-OH)}2 impurities from preparations [C5H3(SiMe3)2]2ScI using samples ScI3 that presumably contain an contaminant.

Language: Английский

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When is a reported air-stable Pr ^IV complex not a Pr ^IV complex? Answer: when it is Pr ^III

Journal of Coordination Chemistry, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 6

Published: July 30, 2024

All the data recently reported for purported air/water stable PrIV complex, [(L)PrIV(L)4(OH0.94Cl0.06)2PrIV(L)]n (L = N-acetylanthranilate) [1], have been reinterpreted to show that it is, in fact, PrIII complex [Pr2L6(H2O)2]n. Importantly, is isomorphous with its EuIII analogue [Eu2L6(H2O)2]n [2], providing further evidence of incorrect assignment literature.

Language: Английский

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